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 A213769 Principal diagonal of the convolution array A213768. 3
 1, 8, 26, 63, 136, 272, 521, 968, 1762, 3159, 5600, 9840, 17169, 29784, 51418, 88399, 151432, 258592, 440345, 747960, 1267586, 2143783, 3618816, 6098208, 10260001, 17236712, 28918106, 48454623, 81093832, 135569264, 226404905 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Clark Kimberling, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (4,-4,-2,4,0,-1). FORMULA a(n) = 4*a(n-1) - 4*a(n-2) - 2*a(n-3) + 4*a(n-4) - a(n-6). G.f.: f(x)/g(x), where f(x) = x*(1 + 4*x - 2*x^2 - 7*x^3) and g(x) = (1 - 2*x + x^3 )^2. MATHEMATICA (See A213768.) LinearRecurrence[{4, -4, -2, 4, 0, -1}, {1, 8, 26, 63, 136, 272}, 40] (* Harvey P. Dale, Jan 08 2015 *) CROSSREFS Cf. A213768, A213500. Sequence in context: A211640 A002901 A350163 * A301647 A050471 A088024 Adjacent sequences: A213766 A213767 A213768 * A213770 A213771 A213772 KEYWORD nonn,easy AUTHOR Clark Kimberling, Jun 21 2012 STATUS approved

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Last modified March 20 14:36 EDT 2023. Contains 361384 sequences. (Running on oeis4.)